Vibginia



UNITED STATES PATENT OFFICE.

ST. GEORGE T. BRYAN, OF UNIVERSITY OF VIRGINIA, VIRGINIA.

PROCESS OF SEPARATING PRECIOUS METALS FROM SPEISS.

SPECIFICATION forming part of Letters Patent 110,336,792, dated February23,1886.

Application filed April 4, 1885. Serial No. 161,234. No specimens.)

To (LZZ whom it may concern:

Be it known that 1, ST. GEORGE T. BRYAN, of the University of Virginia,in the county of Albemarl'e, in the State of Virginia, have invented anew and useful Process of Separating Precious Metals from Speiss, ofwhich the following is a specification.

Speiss is a furnace product, and is essentially iron, lead, gold, andsilver mineralized by arsenic, sulphur, antimony, 85c. Vast amounts ofspeiss are practically at present mere waste for want of a properprocess for its treatment to thoroughly extract the valuable metalscontained in it.

The object of my improvement is to more perfectly and thoroughly extractthe lead and the gold and silver than has heretofore been done. I haveascertained that if air be passed through molten speiss the arsenic andother readily-oxidizable constituents may be easily and entirely burnedoff. On applying the blast at first that portion which mineralizes thelead is removed, and if the air continues to be forced throughtheportion mineralizing the iron is next removed.

My improved method consists in forcing air through molten speiss untilthe arsenic which mineralizes the lead is burned off and the lead setfree. The lead can now be separated from the speiss along with the goldand silver by keeping the mixture fluid, the lead sinking to the bottomof the vessel used. Instead, however, or" depending upon the leadcontained in the speiss to remove all the gold and silver, I mix withthe molten product more lead, which on separating will remove the leadwith the gold and silver originally in the speiss. An oxide of lead maybe used in this process in place of metallic lead,as the arsenic whilepresent will reduce the oxide to the metallic state.

Heretofore, so far as I am aware, there has been no method known bywhich the lead originally in the speiss can be wholly or in partseparated industrially or on a practical commercial scale.

So far as I am aware, there has been heretofore serious loss in lead andgold and silver whenever molten speiss has been treated with lead oritsoxide; but by my process ofcontinually forcing air through the fluidmass and adding lead to the fluid mass I am enabled to greatly increasethe amount of lead and gold and silver taken from the speiss, and, infact, to extract all originally there without material loss or waste.The gold and silver can be separated from the lead after the operationof my improved process in ordinary well-known ways. As by the burning ofthe arsenic much heat is evolved, it will be practicable in well-knownways to utilize this heat for the further fusion of the speiss, and thussave fuel.

Any ordinary furnace adapted for melting speiss may be employed, and anyordinary means for forcing a blast of air through a molten mass may alsobe used.

I am aware that a blast of air has been applied to molten iron forburning out carbon, silica, 82c, and that such a blast has also beenapplied to molten pyritous ores for burning out sulphur, arsenic, &c.,and I do not claim, broadly, the use of a blast of air applied to amolten mass.

Various patents have been granted for the treatment of ores, matte, orregulus for special purposes; but none of them discloses the method oftreating speiss in the way that I do, so as to accomplish the object ofmy pro cess. Of course there is something of similarity in these variouspatented methods to each other and to my process, but not suchsubstantial identity as readers these patented processes interchangablewith each other or with mine. See, for example, United States PatentsNos. 57,376, 130,433, and 234,129, and English Patents No. 390 of 1855,No. 2,913 of 1862, No. 3,892 of 1872, No. 1,131 of 1878, No. 983 of1879, and No. 955 of 1882. All these inventions I disclaim because eachone of them differs more or less from my process for the treatment ofspeiss; but

\Vhat I have discovered and what I claim to be new, and desire to secureby Letters Patent of the United States, is-

The improved process herein described for treating speiss for theextraction of lead and gold and silver, which consists in forcing ablast of air through the molten mass until the I In testimony whereof Ihave hereunto subarsenic and other oxidizable and mineralizscribed myname.

ing constituents are burned off and the lead set ST. GEORGE T. BRYAN.free, carrying with it the gold and silver, and \Vitnesses: 5 addinglead to the molten mass, and continu- MARCUS S. HOPKINS,

ing the blast of air until the lead and gold and GEO. W. MORRIs, silverhave all sunk to the bottom. WM. R. DUKE.

